The Omega Seamaster Planet Ocean 600M Co-Axial Master Chronometer 43.5 mm, reference 215.30.44.21.01.001, is a steel dive watch rated to 600 metres with a helium escape valve. It is the steel-on-steel version with a black ceramic dial and a black ceramic bezel.
Omega launched the Planet Ocean line in 2005. This reference was introduced at Baselworld 2016 as part of the third generation of Planet Ocean models, which moved the three-hand watch to the Master Chronometer caliber 8900.
The 43.5 mm case size had previously been used only on the Planet Ocean GMT. With the 2016 generation it became the standard size for the three-hand model.
Within the lineup, the reference was a regular-production core model: steel case, steel bracelet, and the collection’s black colourway, positioned below the precious-metal, titanium and ceramic Planet Ocean versions.
The dial is made of black zirconium oxide ceramic with a high-gloss finish. The marking [ZrO2] is placed on the dial directly below the central hand stack.
The hour markers are applied polished indexes with luminous fill, combined with applied polished Arabic numerals at 6, 9 and 12. A printed minute and seconds track runs around the dial edge.
The hands are polished and faceted, in the Planet Ocean arrow style, all with luminous fill. The hour and seconds hands emit blue and the minute hand emits green, so the two main hands can be told apart in the dark. The central seconds hand carries an orange tip.
The date sits in a framed window at 3 o’clock. Dial text reads OMEGA with the Omega symbol, “Seamaster” in orange script, “PROFESSIONAL”, “CO-AXIAL”, “MASTER CHRONOMETER” and “600m / 2000ft” in orange, with “SWISS MADE” split either side of 6 o’clock.
The case is round, in stainless steel, with brushed surfaces and polished bevelled edges. It measures 43.5 mm in diameter, 16.09 mm thick and 49.00 mm lug to lug, with a total weight of approximately 214 g.
The crystal is domed sapphire with anti-reflective treatment on both sides. The crown screws in, and a helium escape valve sits on the case flank at 10 o’clock for saturation diving use. Water resistance is 600 metres (60 bar, 2000 feet).
The caseback is an alveol screw-in design with a sapphire display window showing the caliber 8900.
The bezel is unidirectional and carries a polished black ceramic ring with a satin-finished Liquidmetal 60-minute diving scale. A luminous pip at the zero position emits green.
For timing a dive, the wearer rotates the bezel counterclockwise until the pip aligns with the minute hand. Elapsed time is then read directly from the scale against the minute hand. Because the bezel only turns one way, an accidental knock can only shorten the indicated remaining time, never extend it.
The reference is supplied on a stainless steel link bracelet, bracelet code 020STZ004970, with a 21 mm width at the lugs. The bracelet uses screw-attached removable links, part code 114STZ004974.
The clasp is a stainless steel foldover design with push-button release, code 117STZ001159. It carries a six-position micro-adjustment and a diver extension for wearing the watch over a wetsuit.
The micro-adjustment allows the fit to be changed on the wrist without tools, which accommodates swelling in heat or during activity.
The same 43.5 mm case was sold under separate reference suffixes on rubber and leather straps. This reference, 215.30.44.21.01.001, is the steel bracelet version.
The watch uses the Omega Co-Axial Master Chronometer caliber 8900, an in-house self-winding movement. It has 39 jewels, runs at 25,200 vibrations per hour (3.5 Hz) and has a 60-hour power reserve from two barrels mounted in series.
Winding is automatic in both directions. The regulating organ is a free-sprung balance with a Si14 silicon balance spring, paired with the Omega Co-Axial escapement, which reduces friction and lubrication requirements.
The movement is resistant to magnetic fields reaching 15,000 gauss (1.5 tesla). The rotor and bridges are rhodium-plated and decorated with Geneva waves in arabesque.
Certification is two-stage. The movement is first certified as a chronometer to ISO 3159 (-4/+6 seconds per day), then the cased watch passes the eight METAS tests for Master Chronometer status, with a precision criterion of 0/+5 seconds per day.
Functions are hours, minutes, central seconds and date, plus an independently adjustable hour hand.
Operation:
Overall, a steel diver built around hard, non-fading ceramic surfaces on the dial and bezel, with an antimagnetic silicon regulating system.
A full set for a 2023 example contains:
The International Warranty card is completed by the authorised retailer with the 8-digit serial number, reference, purchase date and retailer name and address. The Master Chronometer card gives access to the watch’s METAS test results.
The removed links matter for a full set. A 43.5 mm Planet Ocean bracelet sized for a smaller wrist is incomplete without them, and replacement links are ordered separately under part code 114STZ004974.
Older version (approximately 2016 to mid-2022)
Newer version (approximately mid-2022 to 2025)
The reference ran across both box generations. The change from the glossy box to the satin box with the travel case took place around mid-2022, so a 2023 example is correct in the newer satin box.
The box should match the sale date on the warranty card. A 2023-dated card paired with a glossy box and no travel case points to a box taken from an earlier watch, and a full set missing the red travel case from a newer box is incomplete.
A 2023 purchase carries Omega’s five-year international warranty, which applies to watches purchased from 1 July 2018 onward. The warranty is documented on a red plastic International Warranty card, completed by the authorised retailer and carried in the cream Omega card wallet alongside the red Pictograms and Master Chronometer cards.
At the 2016 launch the same reference, as a Master Chronometer model, carried a four-year factory warranty.
Older version (approximately 2016 to 30 June 2018 sales)
Newer version (1 July 2018 to 2025 sales)
The card set itself did not change across the run, so the sale date on the International Warranty card is what places an example in the four-year or five-year period.
As of September 2026, every example bought before September 2021 is outside its original warranty. A 2023 example remains under factory warranty until the fifth anniversary of its sale date in 2028.
The retailer-completed, dated International Warranty card is the primary document tying the serial number to the sale. A blank or photocopied card, or a set missing one of the three red cards, on an example presented as a full set is a red flag.
The watch wears as a large, tall diver. At 43.5 mm wide and 16.09 mm thick, with a domed crystal, it sits high on the wrist and does not pass under a shirt cuff.
The 49.00 mm lug-to-lug span is compact relative to the diameter, which keeps the lugs inside the edges of most wrists from roughly 17 cm upward. On smaller wrists the case width dominates.
At approximately 214 g on the full bracelet, the head carries most of the weight, and the watch is best worn snug. The micro-adjusting clasp makes that easy to maintain through the day. The helium escape valve on the left flank can contact the back of the hand when the wrist is bent.
The reference suits a wearer who wants a daily steel diver with full saturation-diving specification and visible presence, for casual, outdoor and water use rather than formal dress.
Reference 215.30.44.21.01.001 exists in a single configuration: a 43.5 mm stainless steel case, black ceramic bezel with Liquidmetal scale, polished black ceramic dial with Arabic numerals at 6, 9 and 12, stainless steel bracelet with micro-adjusting diver-extension clasp, and the Master Chronometer caliber 8900.
Neighboring references
These are separate references sharing the 43.5 mm case and caliber 8900. Their specifications do not carry across.
Personalized, end-to-end service to help you buy, sell, and trade with ease
